guard tc6_tc7 clock under min-samd21j feature since the v2 clock depe…

…nds on that feature as well

hal/src/thumbv6m/clock/v1.rs

@@ -401,6 +401,7 @@ impl GenericClockController {
     /// appropriately.
     /// Returns `None` is the specified generic clock has already been
     /// configured.
+    $(#[$attr])*
     pub fn $id(&mut self, generator: &GClock) -> Option<$Type> {
         let bits: u64 = 1<<u8::from(ClockId::$clock) as u64;
         if (self.used_clocks & bits) != 0 {
@@ -445,6 +446,7 @@ clock_generator!(
     (tcc0_tcc1, Tcc0Tcc1Clock, TCC0_TCC1, Tcc0Tcc1),
     (tcc2_tc3, Tcc2Tc3Clock, TCC2_TC3, Tcc2Tc3),
     (tc4_tc5, Tc4Tc5Clock, TC4_TC5, Tc4Tc5),
+    #[cfg(feature = "min-samd21j")]
     (tc6_tc7, Tc6Tc7Clock, TC6_TC7, Tc6Tc7),
     (sercom0_core, Sercom0CoreClock, SERCOM0_CORE, Sercom0),
     (sercom1_core, Sercom1CoreClock, SERCOM1_CORE, Sercom1),